This invention relates to a shooting video game machine having a monitor screen which displays target characters and a mock gun which aims at and shoots the character(s) displayed on the monitor screen.
Conventionally, the shooting video game machine of this type includes a mock gun having a muzzle, a trigger, and a light receiving element arranged on the muzzle and a monitor screen such as a projector having a CRT for projecting game.
Such shooting video game machine is constructed such that when the trigger is pulled, a so-called white screen made only by emission lines by a raster scanning for one frame and the light receiving element receives a light produced during the raster scanning and then a hit position (or a point of impact) by the mock gun is detected by a time elapsed from the beginning of the raster scanning to the time when the light is received by the light receiving element of the mock gun. Thereafter, the judgment is made if the obtained hit position is within the target character displayed on the monitor screen and if the judgment result is affirmative, then it is determined as "hit". It should be noted that hereinafter the word "hit", used throughout this application, is not meant to be an actual hit in physical sense, but is meant to be a virtual hit on the character on the monitor screen by the virtual bullet fired by the mock gun.
With the shooting video game machine above, when the semi-automatic type gun, which sequentially fires bullets during the time the trigger is pulled, is used as a mock gun, the white screen has to come out at each firing timing to detect the hit position. Thus, the number of appearances of white screen in a short period of time is increased, resulting in a reduction of the number game images displayed which; are basically essential images of the monitor screen. As a result, the quality of the screen image is degraded.
As a solution to the above problem, a shooting video game machine is proposed having an infrared light emitter arranged in the predetermined position near the monitor screen for emitting an infrared light and an area sensor, provided on the mock gun, consisting of an image pick-up device made of such as a CCD (Charge Coupled Device) for picking up image of the spot light emitted from the infrared light emitter. Then with this image pick-up device, the light receiving position is detected and then the hit position is obtained. Subsequently, a judgment is made if the hit position is in the target character(s) on the monitor screen or not.
With the thus described shooting video game machine, a switch over of the screen between the white screen and game image screen is not required. Thus it is possible to prevent the degradation of the quality of screen image.
However, even with the later described shooting video game machine, a position detection unit, which detects a hit position of the bullet, has image data, of the infrared spot light captured by the image pick-up device provided on the mock gun, temporarily stored in a frame memory. Thus, the use of the frame memory necessitates a read-in address generating unit for generating read-in frame addresses and a read-out address generating unit for generating read-out addresses corresponding to the certain area within the frame memory. Therefore, structure of the position detection unit is complicated and cost of the shooting video game machine as a whole rises. Accordingly, there exists room for improvement in terms of the structure of the position detection unit.